US20070198076A1

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Publication number: US20070198076A1
Application number: US11/703,342
Authority: US
Inventors: Stephen Hebert; Marc-Alan Levine
Original assignee: Bay Street Medical Inc
Current assignee: Bay Street Medical Inc
Priority date: 2006-02-13
Filing date: 2007-02-07
Publication date: 2007-08-23
Also published as: WO2007095031A2; US20070203563A1; WO2007095031A3

Abstract

A stent delivery system comprising a hypotube, a guidewire extending beyond a distal end of the hypotube and having a first portion and a second portion. The first portion has a second diameter less than the diameter of the hypotube. The second portion of the guidewire has a third diameter less than the second diameter and forming a reduced diameter portion for receiving a stent. A sheath covers at least a portion of the reduced diameter portion of the guidewire.

Description

BACKGROUND

This application claims priority from provisional application No. 60/772,660, filed Feb. 13, 2006, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This application relates to a system for delivering a stent, and more particularly a delivery system wherein a stent is mounted on a hypotube or wire to reduce the overall profile of the system.

BACKGROUND OF RELATED ART

Intravascular stents are used for treatment of vascular stenosis. One type of stents are balloon expandable stents which are mounted over a balloon. Inflation of the balloon expands the stent within the vessel to dilate the stenosis. Another type of stents is self-expanding, composed of shape memory material. The self-expanding stents are compressed within a sheath and when exposed from the sheath automatically move to an expanded shape memorized position within the vessel.

These stents are delivered to the area of stenosis or an aneurysm by a catheter which is inserted over a guidewire. For balloon expandable stents, the balloon is mounted on the outside of the catheter and is expanded by injection of fluid through the catheter. Expansion of the balloon expands the overlying stent. For self-expanding stents, these stents are compressed against the outer surface of the catheter and placed inside a sheath or delivery catheter or positioned. inside the delivery catheter and ejected by a catheter pusher positioned inside the delivery catheter, thereby requiring a larger diameter delivery catheter.

The applicants in an earlier application recognized that utilizing a catheter with a stent mounted thereon did not enable access to small vessels. To reduce the cross-sectional dimension of the stent delivery system, the applicants developed a system for placing a stent on the guidewire or hypotube, rather than on or in the catheter (which was inserted over a guidewire), thereby eliminating the larger dimensioned catheter. This system is described in commonly assigned U.S. Pat. No. 6,989,024, the entire contents of which are incorporated herein by reference, which discloses a stent mounted on a guidewire. The stent is mounted on a reduced diameter portion of the guidewire, resulting in an overall reduced profile. Proximal and distal radiopaque marker bands, functioning as proximal and distal stops for the stent, are also described for certain embodiments.

The apparatus and method disclosed in the '024 patent is effective in accessing smaller vessels and delivering a stent to such vessels. The present application provides improvements and variations to the stent delivery systems disclosed in the '024 patent.

SUMMARY OF THE INVENTION

The present invention in one aspect provides a stent delivery system comprising a hypotube having a first diameter and a guidewire extending beyond a distal end of the hypotube and having a first portion having a second diameter less than the diameter of the hypotube and a second portion having a third diameter less than the second diameter and forming a reduced diameter portion for receiving a stent. A sheath covers at least a portion of the reduced diameter portion of the guidewire and a control member is operatively connected to the sheath and operable to slide the sheath relative to the stent to expose the stent enabling the stent to move to an expanded configuration.

In one embodiment, the guidewire has a longitudinal axis radially offset from and substantially parallel to a longitudinal axis of the hypotube. In one embodiment, the control member comprises a wire connected to a proximal end of the sheath, wherein the wire extends though a lumen in the hypotube and emerges beyond a proximal end of the hypotube. The sheath may have a tapered portion.

The system may further comprise a proximal stop extending from the guidewire and having a transverse cross-section larger than the reduced diameter portion of the guidewire to limit proximal movement of the stent mounted on the guidewire. The stop can be in the form of a radiopaque marker.

In one embodiment, the hypotube has a reduced diameter region and a balloon is mounted on the reduced diameter region. The sheath preferably slides over the reduced diameter region when retracted. In one embodiment, the reduced diameter region is a tapered region. In another embodiment, it is a stepped region which can be formed by a smaller diameter coiled region.

In one embodiment, a valve is movable by the control member such that retraction of the control member moves the valve proximally within the hypotube to seal a channel in the hypotube to enable inflation of the balloon. Preferably in this embodiment, further proximal movement moves the valve within the hypotube lumen to unseal the channel and enable deflation of the balloon and retracts the sheath to expose the stent. Such unsealing could also expose an aperture for aspiration or purging.

The present invention also provides a stent delivery system comprising a hypotube, a guidewire extending beyond a distal end of the hypotube and having a first portion having a second diameter and a second portion having a third diameter. The third diameter is less than the second diameter and forms a reduced diameter portion for receiving a stent. A stop limits proximal movement of the stent.

In one embodiment, the stop is formed by a distal edge of the hypotube. Preferably, the stent is covered during insertion to the surgical site, and uncovering the stent enables it to move to an expanded configuration.

In one embodiment, an enlarged proximal region of the guidewire extends within a lumen of the hypotube and is attached to the hypotube, wherein the enlarged region forms a stop to limit proximal movement of the stent and at least a proximal portion of the stent is positioned within the lumen of the hypotube. In one embodiment, the reduced diameter portion is formed by a stepped portion wherein the second portion is a coiled region stepping down from the hypotube and the first portion is a coiled region stepping up from the second portion.

The present invention also provides a stent delivery system comprising a hypotube having a proximal end, a distal end, a first opening and a reduced diameter portion. A balloon is mounted on the reduced diameter portion of the hypotube and communicates with the first opening. A control member extends within the hypotube and moves a valve from a first position to a second position to block the opening to maintain balloon inflation.

In one embodiment, the hypotube includes an aperture providing communication between a lumen of the hypotube and a vessel of the patient and the valve is movable to a position to block the aperture when the valve is moved to the retracted position. In a preferred embodiment, further retraction of the valve unblocks the opening and opens communication of the aperture.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present disclosure are described herein with reference to the drawings wherein:

FIG. 1 is a perspective view of a first embodiment of the stent delivery system of the present invention;

FIG. 2 is a view similar toFIG. 1 showing retraction of the pull wire to expose the stent;

FIGS. 1A and 2B are views similar toFIGS. 1 and 2 showing an alternate embodiment utilizing a solid tube with a lumen;

FIG. 1B is a perspective view of an alternate embodiment having a tapered hypotube;

FIG. 1C is a perspective view of an alternate embodiment having a tapered sheath;

FIG. 1D is a perspective view of another alternate embodiment having the retraction wire connected to the outside of the sheath;

FIG. 3 illustrates a perspective view of another alternate embodiment of the stent delivery system of the present invention showing the balloon in the deflated condition positioned proximally of the stent and the pull wire in the distal position;

FIG. 4 is a cross-sectional view taken along lines4-4 ofFIG. 3;

FIGS. 4A, 4B and4C are cross-sectional views of another alternate embodiment of the stent delivery system of the present invention having a ball valve at the distal end of the pull wire and shown movable from a first (distal) position to a sealing position and to a retracted unsealing position;

FIG. 5 is a broken perspective view of the distal portion of the system ofFIG. 3, showing the balloon in the inflated condition and the pull wire partially retracted to expose a distal portion of the stent;

FIG. 6 is a cross-sectional view similar toFIG. 4 showing the balloon in the inflated condition, the distally directed arrows representing injection to inflate the balloon and the proximally directed arrow representing retraction of the pull wire to move the valve within the hypotube to seal off the hypotube for balloon inflation;

FIG. 7 is a cross-sectional view similar toFIG. 4 showing the balloon in the deflated condition and the pull wire in the fully retracted position to further retract the valve;

FIG. 8 is perspective view similar toFIG. 3 showing the balloon in the deflated condition and the stent exposed and in its expanded position;

FIGS. 8A and 8B are perspective and cross-sectional views, respectively of another alternate embodiment having a retractable valve;

FIG. 9 is a perspective view of another alternate embodiment of the stent delivery system of the present invention showing the stent in the compressed position and a balloon in a deflated condition underlying the stent, both the stent and balloon shown contained within the sheath (shown partially cut away);

FIG. 9A is a cross-sectional view of another alternate embodiment showing the balloon mounted on a reduced coil section of the guidewire, the stent shown in the collapsed delivery position;

FIG. 9B is a view similar toFIG. 9A showing the balloon and stent expanded;

FIG. 10 is a cross-sectional view taken along lines10-10 ofFIG. 9;

FIG. 11 is a view similar toFIG. 10 showing the sheath further retracted to expose the balloon and stent;

FIG. 12 is a view similar toFIG. 10 showing the balloon inflated to expand the stent;

FIG. 13 is a view similar toFIG. 10 showing the balloon in the deflated condition and the stent remaining in the expanded position;

FIG. 13A is a view similar toFIG. 13 except showing an alternate embodiment for attachment of the wire to the tube;

FIG. 13B is a view similar toFIG. 13A except showing another alternate embodiment;

FIG. 14 is a perspective view in partial cross-section of yet another alternate embodiment of the stent delivery system of the present invention showing a balloon in the deflated condition positioned distally of the stent, the stent shown in the compressed position within the sheath;

FIG. 15 is a cross-sectional view taken along lines15-15 ofFIG. 14;

FIG. 16 is a view similar toFIG. 15 showing the balloon in the inflated condition and the stent in the compressed position within the sheath;

FIG. 17 is a view similar toFIG. 15 showing the balloon in the deflated condition and the stent in the expanded position exposed from the sheath;

FIG. 18 illustrates another alternate embodiment of the stent delivery system of the present invention showing the stent in the compressed condition within the catheter;

FIG. 19 is a close up perspective view of the area of detail denoted inFIG. 18 showing the stent in the expanded position exposed from the catheter;

FIG. 20 is a perspective view in partial cross section of still another alternate embodiment of the stent delivery system of the present invention showing the core wire with an enlarged back end positioned within a hypotube and the stent in the compressed position;

FIG. 21 is a cross-sectional view showing partial expansion of the stent ofFIG. 20;

FIG. 22 is a view similar toFIG. 21 showing full expansion of the stent;

FIG. 23 is a perspective view in partial cross section of another alternate embodiment of the stent delivery system of the present invention showing the stent in a compressed position with the distal portion covered by a shrink wrap;

FIG. 24 is a cross-sectional view of the system ofFIG. 23 showing the shrink wrap advanced from the hypotube and the stent partially expanded;

FIG. 25 is a view similar toFIG. 24 showing the stent in the fully expanded position with the shrink wrap collapsed on the guidewire;

FIG. 26 is a perspective view in partial cross-section of another embodiment of the stent delivery system of the present invention showing the stent in a compressed condition;

FIG. 27 is a cross-sectional view of the system ofFIG. 26 showing the stent partially expanded as it is partially advanced from the hypotube;

FIG. 28 is a view similar toFIG. 27 showing the stent in the fully expanded position;

FIG. 29 is a perspective partial cross-sectional view of another embodiment of the stent delivery system having different sized guidewire coils;

FIGS. 30-30B are perspective views of alternate embodiments of a plastic guide for mounting the stent;

FIG. 31 illustrates a side view of yet another alternate embodiment of the stent delivery system of the present invention, the stent shown in the collapsed position within the catheter;

FIG. 31A is a close up view of the area of detail denoted inFIG. 30;

FIG. 32 is a view similar toFIG. 31 showing retraction of the catheter to expose the stent;

FIG. 33 illustrates movement of the tube to expand the middle portion of the stent ofFIG. 30;

FIG. 34 is a view similar toFIG. 33 showing the stent in the expanded position, released at both ends from the tubes;

FIG. 35 illustrates a cross-sectional view of still another alternate embodiment of the stent delivery system of the present invention, the stent shown in the collapsed position within the sheath; and

FIG. 36 is a view similar toFIG. 35 showing the stent in the expanded position exposed from the sheath.

DETAILED DESCIRPTION OF PREFERRED EMBODIMENTS

Referring now in detail to the drawings wherein like reference numerals identify similar or like components throughout the several views, a first embodiment of the stent delivery system of the present invention is shown inFIGS. 1 and 2. In this embodiment, stent delivery system is represented generally byreference numeral10 and includes ahypotube12, a tapered core wire (guidewire)20 extending beyond a distal end of thehypotube12, a sheath ortube30 covering the stent, and a control member in the form of apull wire40. Theguide wire20 is attached at a proximal end to the distal end region14 of thehypotube12 by soldering to the inside wall of the hypotube, by welding or other attachment means. As illustrated, thecore wire20 is located off center from and preferably substantially parallel to a central longitudinal axis of thehypotube12 and has a smaller diameter than the hypotube. Pullwire40 extends throughlumen15 in thehypotube12 so it emerges beyond a proximal end17 of thehypotube12 to be manipulated by the user. Thepull wire40 is also off center from and substantially parallel to the longitudinal axis of thehypotube12. The distal end42 ofwire40 is attached to aproximal end region32 ofsheath30.

Stent

50 is mounted oncore wire20 inregion22, which is preferably tapered or otherwise reduced in diameter, such as by a stepped portion (not shown in this embodiment but illustrated in other embodiments). Aproximal stop24, which can be integral with thewire20 or a separately attached component, limits proximal movement of thestent50 and is shown by way of example as a circular disk-like member, although other configurations are contemplated. Thestop24 can also be in the form of a radiopaque marker or coil to enhance imaging. Thestop24 has a transverse cross-section or outer diameter larger than the reduceddiameter portion22 ofguidewire20. By mounting the stent on the core wire, and on the tapered reduceddiameter region22 of the core wire, an overall reduced profile of the delivery system is achieved. The advantages of such reduced profile mounting in this embodiment as well as the other embodiments discussed below are described in detail in U.S. Pat. No. 6,989,024 and commonly assigned co-pending U.S. application Ser. No. 11/248,362, filed Oct. 11, 2005, the entire contents of which are incorporated herein by reference.

In use, after the system is inserted to the surgical site, thepull wire40 is pulled proximally in the direction of the arrow ofFIG. 2 to slide the attachedsheath30 proximally to expose thestent50 positioned on the reduceddiameter portion22. This allows the self expanding stent, preferably composed of shape memory material such as Nitinol or elgiloy, although other shape memory materials are also contemplated, to expand from its compressed (collapsed) position within sheath30 (as shown inFIG. 1) to its expanded configuration shown inFIG. 2. Note in the fully retracted position, theproximal end32 ofsheath30 abutsdistal edge19 ofhypotube12, thus limiting proximal movement ofsheath30.

Note the stents of the embodiments disclosed herein can be composed of shape memory, stainless steel or other metals or metal composites and of radiopaque material.

FIGS. 1A and 2B illustrate an alternate embodiment of the stent delivery system utilizing a solid tube instead of the hollow hypotube ofFIG. 1.Solid tube60 has a lumen preferably extending substantially parallel to the longitudinal axis of thetube60 to slidably receivepull wire64. In other respects, the system is similar toFIG. 1, having aguidewire70 attached to thedistal end region66 of the tube60 (preferably extending into a small bore formed therein) and extending substantially parallel to a longitudinal axis thereof.Stent50′ is mounted on a reduceddiameter portion72 ofguidewire70 and asolid tube80 coveringstent50′ is controlled bypull wire64.

The tubes and/or sheaths disclosed in the various embodiments herein could have slits. They can be composed of composite material, and can contain a Teflon liner with a soft outer jacket. The hypotube disclosed herein can be made of various materials, including for example, a composite with layered materials, a polymer fused together which can include a liner or braid.

In the alternate embodiment ofFIG. 1B, instead of a gap between the tube and sheath, hypotube90 is tapered atregion95 so that when sheath ortube94 is retracted bypull wire92, it slides over the taperedportion95 oftube90. Proximal movement of thesheath94 is stopped when itsproximal end96 contacts matchingdiameter portion91 ofhypotube90.

In the alternate embodiment ofFIG. 1C, sheath30ais tapered. The smaller diameter tapered region31aoverlies and compresses the stent50a. The pull wire40ais attached to the larger diameter region31b. Thewire20a, extending from hypotube12a, has aradiopaque region40bat its distal tip which can be coiled as shown or made of polymeric material and/or coated with radiopaque ink. Such coil, polymeric material and coating can be utilized with the other embodiments described herein. In all other respects, the system ofFIG. 1C operates similar to that ofFIG. 1, e.g. pull wire40ais retracted until proximal end31cof sheath30aabuts distal end12bof hypotube12a.

In the alternate embodiment ofFIG. 1D, pull wire40gis attached to anouter surface31hof sheath30g. The system ofFIG. 1D in all other respects is similar to that ofFIG. 1, with the pull wire40gretracting sheath30gto expose the stent50g. The wire20ghas a coiledradiopaque region20hat its distal tip. Note, as inFIG. 1C, the coil is shown with a diameter substantially equal to the diameter of the sheath, but alternatively it could be smaller. The coil could also extend back to cover the sheath.

FIG. 3 illustrates an alternate embodiment of the stent delivery system, designated generally byreference numeral100. Thesystem100 includes ahypotube112, core (guide)wire120 extending beyond adistal end114 ofhypotube112, aballoon160, and apull wire140 for controlling sliding movement of sheath ortube130. Thehypotube112 preferably has a taperedregion116 on whichballoon160, e.g. an angioplasty balloon, is mounted.Stent150 is mounted on thecore wire120, preferably on a tapered or reduced diameter region.Core wire120 extends fromdistal end114 ofhypotube112 and is attached thereto. Aproximal stop124, which can be integral with thewire120 or a separately attached component, limits proximal movement of the stent. Thestop124 can also be in the form of a radiopaque marker to enhance imaging.Injection port145 fluidly communicates with alumen119 in thehypotube112 viatube147. Thehypotube lumen119 communicates with an opening in theballoon160 to allow inflation of the balloon. Note in an alternate embodiment of a solid tube, a lumen would be formed to communicate with the balloon for inflation and for the pull wire.

Pullwire140 is attached at itsdistal end142 tosheath130 by conventional attachment methods. A ball or other shapedvalve144 is mounted on or integral withpull wire140. When thepull wire140 is in the position ofFIG. 4, theballoon160 is deflated and thesheath130 covers thestent150 to hold it in the reduced diameter compressed condition. In this position, thechannel118 can form a passageway for suction in the direction shown by the arrows inFIG. 4.

When thepull wire140 is retracted proximally in the direction of arrow A inFIG. 6 by pulling on its proximal end,ball valve144 is moved proximally withinhypotube112 to seal offchannel118 ofhypotube112 so the inflation fluid does not exit throughchannel118 but passes through theopening115 in thehypotube112 and through the alignedopening162 inballoon160 to inflate the balloon. This position of theball valve144 with theinflated balloon160 is shown inFIG. 6. In this position,stent150 remains at least partially covered bysheath130, as shown inFIG. 5. (Note in alternate embodiments, e.g. by adjusting the length of the sheath, stent uncovering can occur simultaneously with balloon inflation.) Next, pullwire140 is retracted further, as indicated by the arrow ofFIG. 7, to pullball valve144 proximally within thehypotube lumen119, proximal ofchannel118, to no longer seal thechannel118 as thevalve144 is located in a larger internal diameter region of thehypotube112. This enables deflation of theballoon160, indicated by the proximally directed arrows withinlumen119 ofFIG. 7. Sufficient proximal movement ofpull wire140 retracts the sheath130 a sufficient distance so that the self-expandingstent150 is uncovered, thereby allowing it to expand from its collapsed position to its expanded position shown inFIG. 8.

FIGS. 4A-4C illustrate an alternate embodiment of the stent delivery system having aball valve172 mounted on or integral with the distal end of concentrically positionedwire170. Initially, thevalve172 is in the first distal position ofFIG. 4A where it is forward of opening186 andaperture173.Aperture173 can be used to purge the catheter in a preparatory step as well as for aspiration as it provides communication between thelumen182 ofhypotube180 and the patient. The balloon, preferably mounted on a reduced diameter portion of the hypotube, is inflated and thevalve172 is retracted by wire170 (FIG. 4B) to a sealing or blocking position whereinvalve172 blocks opening186 oflumen182 ofhypotube180 to maintain inflation ofballoon175 to expandstent190. Note relative movement ofsheath192 ofhypotube180 exposes theballoon175 andstent190 for expansion as shown inFIG. 4B. When the valve is retracted further to the position ofFIG. 4C by the control member in the form ofwire170, the balloon can be deflated andaperture173 is open for communication with the patient for aspiration. Although only a single opening and single aperture is shown, multiple openings and/or apertures could be provided. A detachable proximal luer (not shown) can be provided.

FIGS. 8A and 8B illustrate another alternate embodiment having avalve902 with anopening904 to receive pullwire control member906 and anopening908 to receiveguidewire910.Stent912 is positioned withinsheath914 which is retractable in the same manner as the sheath ofFIG. 1. When thevalve902 is retracted after inflation of balloon916 (the stent not shown inFIG. 8B), it is retracted to cover opening918 to maintain balloon inflation.Guidewire910 is welded or attached by other means to an inner surface ofhypotube920 atproximal end911 and bends slightly upwardly to provide agap917 to accommodate retraction ofvalve902 as it rides overguidewire910.

In the alternate embodiment ofFIGS. 9A and 9B, theballoon704 andstent706 on mounted on a reduced diameter coil portion of the guidewire. As shown, guidewire710 has a reducedcoil section712 extending fromhypotube720. An enlarged coil section of guidewire710 is designated byreference numeral714. Thus, a stepped portion instead of a taper as inFIG. 10 is provided. Thehypotube720, as with the other hypotubes disclosed herein, can havecutouts728 to increase the flexibility and steerability. As in other embodiments described herein, relative movement of thesheath732 exposes the stent and balloon for expansion. The delivery position of the stent is shown inFIG. 9A; the expanded placement position is shown inFIG. 9B.

In the alternate embodiment ofFIGS. 9-13, thehypotube220 ofdelivery system200 has acore wire225 attached to and extending distally therefrom. Anenlarged region226 can form the attachment area as well as provide a proximal stop for the stent (which could also be radiopaque for imaging) similar to stop24 described above.Balloon210 is mounted on a tapered or otherwise reduceddiameter portion222 ofcore225 and underliesstent230. The taperedportion222 reduces the overall profile of thesystem200. In an alternate embodiment, instead of an attached core wire, the hypotube itself would have a reduced diameter portion with a balloon mounted thereon and a stent overlying the balloon, as shown inFIG. 13B. Thestent230 can be a self expanding stent, such as of shape memory material, with the balloon inflated to further expand the stent once self-expanded. The stent can alternatively be a balloon expandable stent, relying on the balloon inflation for expansion. As with the other embodiments disclosed herein, thestent230 is preferably mounted on the reduceddiameter region222 which could include a taper, a stepped down region or other structure. The injection port and tube for the inflation fluid for theballoon210 is designated by

reference numerals

228,229, respectively, and communicates withlumen227 ofhypotube220 which has anopening229 aligned with an opening in theballoon210. Thehypotube220 can be hollow or solid with a lumen formed therein as described above with other embodiments. A sheath or catheter which maintains the stent in the compressed position by preventing expansion of the balloon and/or stent is designated byreference numeral235.

In use, retraction of the sheath or catheter235 (or advancement of thehypotube220 or opposite movement of both) enables balloon expansion and stent expansion by exposure of thestent230 andballoon210, as shown inFIG. 12. After expansion of thestent230, the balloon is deflated (see arrows ofFIG. 13) and the delivery system withdrawn, leaving the stent in the vessel.

FIG. 13A illustrates an alternate way to attach the guidewire to the hypotube. InFIG. 13A, hypotube220ahas an overcut220bover which the undercut225bof core wire225aoverlies and is attached thereto. In the embodiment ofFIG. 13B, hypotube240 has a reduced diameter portion in the form of a stepped down portion242 with aballoon243 mounted thereon and a stent244 overlying theballoon243. Hypotube also tapers as shown.

In the alternate embodiment ofFIGS. 14-17,delivery system250 has a hypotube262, shown solid with

lumens

264 and267 formed therein, but alternatively could be hollow as inFIG. 1 with separate tubes positioned therein to form the lumens/passageways. As shown inFIG. 15, a taperedcore wire263 extends from a distal end of hypotube262 and has anenlarged region271, attached to hypotube262, similar toregion226 of theFIG. 9 embodiment to form a stop. Instead of an attached core, alternatively, the hypotube itself could be tapered.Lumen264 communicates with opening265 for fluid injection to inflateballoon255 andsuction lumen267 communicates with opening269 for aspirating clot (see arrows ofFIG. 16).Injection port270 communicates with theinflation lumen264 andsuction port274 communicates withsuction lumen267.Balloon255 is shown positioned distally of thestent280 and is inflated to block the vessel lumen to enable aspiration throughhole269 in hypotube262.Proximal stop271 is provided oncore263 and functions as described above with respect to stop24. A sheath or catheter is designated byreference numeral290.Stent280 is mounted on a tapered or otherwise reduced diameter portion of thecore wire263 as is theballoon255. A coiled radiopaque wire (not shown) for imaging can be provided on the hypotube distal tip or core wire in this embodiment as well as the other embodiments described herein.

Relative movement ofsheath290 and hypotube262, e.g. retraction ofsheath290, advancement of hypotube262 or movement of both in opposite directions, exposesstent280 for self-expansion.FIG. 16 illustrates theballoon255 expanded with thestent280 remaining in the compressed or collapsed position within thesheath290.FIG. 17 illustrates thestent280 exposed from thesheath290 and in its expanded configuration, with theballoon255 deflated so it can be withdrawn through the stent so the system can be removed from the body.

FIGS. 18 and 19 illustrate another alternate delivery system designated generally byreference numeral300.System300 includes ahypotube312, a wire (guidewire)320, and asheath330. Preferably thehypotube312 is closed, e.g. by soldering, at both ends to form a closed tube.Wire320 is attached to thedistal end314 of hypotube such as by soldering or other means to extend distally therefrom and preferably has a region of smaller diameter than thehypotube312. By way of example, the hypotube could have a diameter of about 0.008 inches to about 0.043 inches, and preferably about 0.016 inches, and the wire could have a diameter of about 0.003 inches to about 0.040 inches, and preferably about 0.016 inches, with the stepped down or reduced diameter area preferably of about 0.0095 inches. Thedistal edge314 of thehypotube312 can act as a proximal stop to limit proximal movement of thestent340 which is mounted on the reduceddiameter coil section321 ofwire320 insidesheath330. The largerdistal coil section322, in a preferred embodiment, has a diameter substantially equal to the diameter of the hypotube atdistal section315, although alternately it could be of larger or smaller diameter than the hypotube. Mounting of thestent340 on the smaller diameter wire, in the stepped down region formed on thecoiled section321 between larger diameter hypotube312 and largerdiameter coil section322, reduces the overall profile of the system as described above. Sheath orcatheter330 is slidable relative to thehypotube312 andwire320 to expose thestent340 to enable it to self expand from its compressed condition ofFIG. 18 to its expanded position ofFIG. 19. Aninjection port331 can optionally be provided.

FIGS. 20-22 illustrate an alternative way of mounting a smaller diameter core wire to a hypotube. Thecore wire359, shown in this embodiment as coiled, has an enlarged back end352 which is soldered to thehypotube360 atregion355. This enlarged region352 also functions as a stop to limit proximal movement of the stent. Thehypotube360 is inserted through a catheter orsheath370 which maintains thestent340 in a compressed position. Whensheath370 is retracted and/orhypotube360 advanced, thedistal end341 of thestent340 is exposed causing it to self-expand as shown inFIG. 21. After the distal and

intermediate portions

341,343 ofstent340 expand, the proximal end344 is pulled by the expansion force of the stent from the confines of thehypotube360 so thestent340 moves to the expanded position shown inFIG. 22. The hypotube can be pulled back to further aid expansion.

FIGS. 23-25 illustrate another alternate delivery system designated generally by reference numeral400. Core wire orguidewire420 has a tapered or otherwise reduced region, beginning at transition region422 and extending intofirst coil section423, to form a reduceddiameter region425 for mountingstent440 in a low profile manner. The larger diameter distal coil region ofwire420 is designated byreference numeral427. Thus, the reduced diameter portion ofFIGS. 23-25 is formed by the core stepping down to a reduceddiameter coil section423 and stepping up to largerdiameter coil region427.Guidewire420 is slidably positioned withinhypotube412. Flexible material, illustratively shown asshrink tubing430, is attached at itsdistal end432 to guidewire420 (at radiopaque coil region) and positioned overdistal end414 ofhypotube412 to provide a smoother transition. Thetubing430, which extends from the guidewire to the hypotube, could optionally be attached to the outer distal region of thehypotube412.

When guidewire420 is slid forward to carrystent440 past thedistal end414 ofhypotube412, shrinktubing430 will disengage fromhypotube412 as shown inFIG. 24 by the force ofguidewire420. Thestent440, being exposed from thehypotube412, can expand from its compressed position. Thestent440 will expand first in itsmiddle region447 and then the proximal region446 (since itsdistal region445 initially remains within shrink tubing430), followed by expansion of thedistal region445 due to the expansion forces of the other portions of thestent440. The wire can optionally be pushed forward to further release it from the tubing.FIG. 24 shows the proximal and

intermediate portions

446,447, respectively, of thestent440 expanded and thedistal region445 initially held with thetubing430;FIG. 25 shows full expansion of thestent440 as the expansion forces cause thedistal region445 to free itself from thetubing430. Shrink tubing has collapsed onguidewire420. Note the radiopaque coils are shown at a distal region ofcore wire420. In alternate embodiments, the coil(s) can extend along a larger region ofwire420 and as long as the whole length. Also different sized coils can be provided. An example of different sized coil regions is shown inFIG. 29 where guidewire490 has large coiledregion492 and smallercoiled region494. Stent497 is positioned distal ofregion492 and onregion494. Such coil of different lengths and different sizes can be used in each of the embodiments described herein.

In the alternate embodiment ofFIGS. 26-28,delivery system450 has ahypotube452, a tapered core orguide wire460, and flexible material, shown asshrink tubing480, attached at adistal end482 to thewire460 and positioned over thedistal end454 ofhypotube452 to provide a smoother transition. Thetubing480, which extends from the guidewire to the hypotube, could optionally be attached to the outer distal region of thehypotube452.Stent470 is positioned on a tapered or otherwise reduced diameter coiledportion462 of wire460 (at radiopaque coil region) proximal ofshrink tubing480. As shown, coiledportion462 steps up to larger diameter coiledportion463. As thewire460 is moved forward to expose the stent fromhypotube452, shrinktubing480 collapses on the distal region461 (which includes enlarged coil section463) ofwire460 and the distal and

intermediate regions

477,479, respectively, of thestent470 expand as shown inFIG. 27. Thewire460 continues to be pushed forward untilstent470 extends past thedistal end454 ofhypotube452 to expose the stent to enable it to self expand to the expanded configuration (seeFIG. 28). Note the radiopaque coil is shown at a distal region ofcore wire420. As noted above, in alternate embodiments, it can extend along a larger region ofwire420, including the whole length. Also different sized coils can be provided such as large coil region and smaller coil region.

Instead of a shrink tubing inFIGS. 23-28, an elastomeric tube could be utilized, as well as other materials which can collapse, for example, Nitinol, silicone, composite silicone, and a coil tube.

In the alternate embodiment ofFIG. 29, alarge coil region492 of core wire490 is positioned behind thestent494. Thestent494 is positioned on a reduced diameter coiledsection496, preferably tapered in a distal direction although alternatively could be of a substantially uniform reduced diameter.

FIG. 30-30B illustrate alternate embodiments of a plastic guidewire for mounting the stents. InFIG. 30,guide800 has acore wire802 embedded therein. Stent806 is mounted on the reduced diameter cut out or stepped region804. InFIG. 30A, plastic guide810 has acore wire812 and a cut out or stepped region814 for mounting the stent816. Radiopaque distal and proximal marker bands819,818 are provided. Agap815a,815bcan optionally be provided between the ends of the stent806 and guide810 to allow slight axial movement of the stent806 to aid release of the stent. InFIG. 30B, theplastic guide820 has acore wire822 and reduced diameter region in the form of a stepped or cut out region824. Aslot827 is molded into the plastic to receive aproximal portion827 ofstent826 underneath to retain the proximal portion. The stents in these embodiments are shown in the collapsed position withinrespective sheaths805,815 and825.

In the embodiment ofFIGS. 31-34, the delivery system includes ahypotube512 and a smaller diameter guidewire520 having aradiopaque coil522 for imaging at its distal end. Ahypotube514 or alternatively a marker band or other radiopaque member is soldered or otherwise attached to theguidewire520 adjacent or over theradiopaque coil522. Astent550 is positioned coaxially onregion526 of guidewire520 (which optionally could be of further reduced diameter). In the delivery position of the system, thedistal end551 of thestent550 is pressed within the openproximal end517 ofhypotube514 and theproximal end552 of thestent550 is pressed within the opendistal end515 ofhypotube512.Hypotube512 is then pulled proximally in the direction of arrow13 to stretch and collapse thestent550 to the delivery position ofFIG. 31.

Thehypotube512 and guidewire520 are then inserted through catheter orsheath540. To deploy thestent550, hypotube512 is moved distally in the direction of arrow C inFIG. 33. This expands themiddle region553 ofstent550 which then releases the distal and proximal ends551,552 from

tubes

514,512, by the expansion force of themiddle region553 to enable expansion of thestent550 to the position shown inFIG. 34. The hypotube or wire can be moved to aid expansion. As with the other embodiments described herein, after stent expansion, the delivery system is withdrawn leaving the expanded stent in the vessel.

In the embodiment ofFIGS. 35 and 36, the stent delivery system is designated byreference numeral600 and includes a microcatheter, hypotube orsheath610, aguidewire620 and aplunger630.Stent650 is mounted on theguidewire620, preferably on a reduced diameter coiled region, distal of thedistal edge632 ofplunger630 and proximal of enlargedcoiled region621. Thedistal edge632 also functions as a stop to limit proximal movement of thestent650. The stent is maintained in a compressed configuration by themicrocatheter610 when theguidewire630 is inserted therein. Thus thestent650 is captured between coiledregion621 andplunger630 so the stent can be retracted within the sheath. Whenplunger630 is advanced distally, thestent650 is moved distally along theguidewire620 past the distal edge of themicrocatheter610 to enable expansion. Theguidewire620 can be inserted intolumen612 of an already placed microcatheter or alternatively can be inserted into the microcatheter or hypotube before its placement and then the assembly inserted to the surgical site.

In the foregoing embodiments of changing diameter hypotubes, the diameter of the hypotube may preferably range from about 0.20 inches at its largest portion to about 0.010 inches at its smallest portion, and more preferably about 0.019 inches and about 0.015 inches, respectively.

In the foregoing embodiments, the sheath which constrains the stent (and balloon) can be inserted with the stent mounted hypotube/guidewire as a single system. Alternatively, the sheath can be placed in the body, and the stent mounted hypotube/guidewire delivered through the already placed sheath.

While the above description contains many specifics, those specifics should not be construed as limitations on the scope of the disclosure, but merely as exemplifications of preferred embodiments thereof. For example, the hypotubes of the foregoing embodiments could include slots for flexibility. A metal or reinforced plastic tube could be utilized. Also in the foregoing embodiments, a distal stop, either integral or attached, and made of a radiopaque material for imaging, could be provided. Further, to provide a reduced diameter mounting region, as an alternative to a taper, a stepped region or cut out region could be provided. The tip of the wire could be shapeable. Additionally, to expose the stent, the stent mounted hypotube/guidewire could be advanced from the sheath, the sheath could be retracted, or both could be moved in opposite directions. Those skilled in the art will envision many other possible variations that are within the scope and spirit of the disclosure.

Claims

1. A stent delivery system comprising:

a hypotube having a proximal end, a distal end and a first diameter;

a guidewire extending beyond a distal end of the hypotube and having a first portion and a second portion, the first portion having a second diameter, the second diameter of the guidewire being less than the first diameter of the hypotube, the guidewire including a second portion having a third diameter, the third diameter being less than the second diameter and forming a reduced diameter portion for receiving a stent;

a sheath covering at least a portion of the reduced diameter portion of the guidewire; and

a control member operatively connected to the sheath, the control member being operable to slide the sheath relative to the stent to expose the stent enabling the stent to move to an expanded configuration.

2. The stent delivery system as recited inclaim 1, wherein the hypotube has a central longitudinal axis and the guidewire has a longitudinal axis radially offset from the longitudinal axis of the hypotube and substantially parallel to the longitudinal axis of the hypotube.

3. The stent delivery system as recited inclaim 1, wherein the control member comprises a wire connected to a proximal end of the sheath, the wire extending though a lumen in the hypotube and emerging beyond a proximal end of the hypotube.

4. The stent delivery system as recited inclaim 3, wherein the wire has a longitudinal axis radially offset from the longitudinal axis of the hypotube and substantially parallel to the longitudinal axis of the hypotube.

5. The stent delivery system as recited inclaim 1, further comprising a stent mounted on the reduced diameter portion of the guidewire.

6. The stent delivery system as recited inclaim 1, further comprising a proximal stop extending from the guidewire, the stop having a transverse cross-section larger than the reduced diameter portion of the guidewire to limit proximal movement of the stent.

7. The stent delivery system as recited inclaim 1, wherein the hypotube has a reduced diameter region, and further comprising a balloon mounted on the reduced diameter region of the hypotube.

8. The stent delivery system ofclaim 1, wherein the hypotube has a reduced diameter region, the sheath sliding over the reduced diameter region of the hypotube when the sheath is moved to a retracted position.

9. The stent delivery system as recited inclaim 1, further comprising a balloon mounted on the hypotube and a valve movable by the control member, wherein retraction of the control member moves the valve proximally within the hypotube to seal a channel in the hypotube to enable inflation of the balloon.

10. The stent delivery system as recited inclaim 9, wherein further proximal movement of the control member moves the valve within a hypotube lumen to unseal the channel and enable deflation of the balloon and sufficient retraction of the sheath to expose the stent.

11. A stent delivery system ofclaim 1, wherein the sheath has a first diameter portion overlying the stent and a second larger diameter portion proximal of the first diameter portion, the control member attached to the sheath at the second diameter portion of the sheath.

12. A stent delivery system comprising:

a hypotube having a proximal end, a distal end and a first diameter;

a guidewire extending beyond a distal end of the hypotube and having a first portion, the first portion having a second diameter, the guidewire including a second portion having a third diameter, the third diameter being less than the second diameter and forming a reduced diameter portion for receiving a stent; and

a stop limiting proximal movement of the stent.

13. The stent delivery system as recited inclaim 12, wherein the stop is formed by a distal edge of the hypotube.

14. The stent delivery system ofclaim 12, wherein the reduced diameter portion is formed by a stepped portion wherein the second portion is a coiled region stepping down from the hypotube and the first portion is a coiled region stepping up from the second portion.

15. The stent delivery system as recited inclaim 12, wherein the stent is covered during insertion to a surgical site, and uncovering the stent enables it to move to an expanded configuration.

16. The stent delivery system as recited inclaim 12, wherein an enlarged proximal end region of the guidewire extends within a lumen of the hypotube and is attached to the hypotube, the enlarged region forming a stop to limit proximal movement of the stent, and at least a proximal portion of the stent is positioned within the lumen of the hypotube.

17. A stent delivery system comprising:

a hypotube having a proximal end, a distal end and a first opening, the hypotube having a reduced diameter portion;

a balloon mounted on the reduced diameter portion of the hypotube and communicating with the first opening;

a valve;

a control member extending within the hypotube, the control member moving the valve from a first position to a second position to block the opening to maintain balloon inflation.

18. The stent delivery system ofclaim 17, wherein the hypotube includes an aperture providing communication between a lumen of the hypotube and a vessel of a patient, the valve blocking the communication when the valve is moved to the second position.

19. The stent delivery system ofclaim 18, wherein further retraction of the valve unblocks the opening and opens communication of the aperture.